Consider the following SQL statement. SELECT qty FROM sales WHERE rate IN (300,800); Which of the following operators can be used to substitute the 'IN' operator?

To solve this question, the user needs to understand the different SQL operators and how they work. The user must also know how to use these operators in a SQL statement to perform a specific task.

Now, let's go through each option and explain whether it can be used to substitute the 'IN' operator:

A. ALL: The ALL operator is used to compare a value to all values in another set of values. It cannot be used to substitute the 'IN' operator. Therefore, option A is incorrect.

B. BETWEEN...AND: The BETWEEN...AND operator is used to select values within a given range. It cannot be used to substitute the 'IN' operator. Therefore, option B is incorrect.

C. LIKE: The LIKE operator is used to compare a value to similar values using wildcard characters. It cannot be used to substitute the 'IN' operator. Therefore, option C is incorrect.

D. OR: The OR operator is used to combine multiple conditions in a WHERE clause. It can be used to substitute the 'IN' operator by specifying each value as a separate condition joined by the OR operator. Therefore, option D is correct.

The Answer is: D